Women with great bodies have a dirty little secret. Sure, they work out and eat well — but they also sneakily burn hundreds more calories than everyone else. From the outside, they don't seem to be doing anything particularly strenuous. "You wouldn't believe how many straightforward ways there are to burn calories," says Lauren Slayton, director of foodtrainers.net. "But it's easy to miss the opportunities if you're not looking for them."

Research has shown that swapping sedentary habits, such as watching television, for pretty much anything that doesn't involve sitting down can make a world of difference. "Most people don't realize that a little extra effort can yield great results," says Steven Wheelock, a trainer at Canyon Ranch in Lenox, Massachusetts.

The experts we consulted explain how to take every opportunity to flex your muscles, boost your heart rate, and eat foods that yield maximum fullness for minimal calories. Just don't tell anyone.

1. Take vitamin D
Women who were deficient in it lost weight more slowly in a study in the British Journal of Nutrition. Stephen Gullo, a weight-loss expert in New York City and author of "The Thin Commandments" (Rodale), recommends 2,000 milligrams daily.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

2. Drink coffee
Studies have found that caffeine increases the rate at which you burn calories, according to Susan B. Roberts, author of "The 'I' Diet" (Workman) and a professor of nutrition and psychiatry at Tufts University in Boston.

3. Sleep more
Getting fewer than four hours of sleep over an extended period of time slows the metabolism. Experts recommend aiming for between seven and nine.

5. Wear a basic pedometer
"Every week, aim to take a few more steps than you did the last week," says Wheelock.

6. Eat lightly and often
"For most people, the body uses up more energy digesting smaller meals every few hours than by eating the same number of calories in two or three sittings," says Chrissy Wellington, a nutritionist at Canyon Ranch in Lenox, Massachusetts.

7. Move briskly
"Walk like you're late for a meeting," says Gunnar Peterson, who trains Jennifer Lopez in Los Angeles.

8. Laugh
"It burns up to 50 calories if you laugh for 10 to 15 minutes per day," says Adelino Da Costa, owner of Punch Fitness Center in New York City.

10. Time yourself
Spend the last five minutes of each hour (set your computer timer) up and moving around, says Kristin McGee, a New York City yoga and Pilates instructor.

11. Fill up on fiber
Low-carb, high-fiber foods take more time to digest than other foods, leaving you feeling fuller longer and less likely to snack, says Gullo. He suggests spinach, broccoli, asparagus, and cauliflower.

12. Go out of your way
At work, take the long way to the restroom — or even go up one flight of stairs.

13. Fidget
You can burn up to 350 more calories a day than someone who remains stationary, according to a study at the Mayo Clinic. The impulse to fidget may be hardwired, but nonfidgeters can imitate it: Tap your feet, pace, or move restlessly in your seat.

14. Stash flats in your bag
"My clients aren't going to slip on sneakers to go home, but there is a happy medium," says Slayton. "You might not run a marathon in ballet slippers, but at least you can move quickly."

15. Don't eat late at night
It can interrupt sleep, according to Wellington, and may induce you to skip breakfast — bad for your metabolism.

16. Straighten up
"Good posture not only makes you look taller and leaner, but it strengthens your abdominal muscles," says Brooklyn Decker, the model on the cover of this year's Sports Illustrated swimsuit issue.

17. Drink more
Dehydrated people experience a drop in their metabolic rate. Drinking water throughout the day caused metabolic rates to increase by about 30 percent in a German study. The goal: eight cups a day.

18. Beware of sugar
It triggers the body to release insulin, which then either transplants sugar to the cells to be used as energy — or stored as fat, according to Jorge Cruise, author of "The Belly Fat Cure" (Hay House).

19. Squat
When you pick up something from the floor, keep your back straight and bend at the knees, not the waist. "This protects your back and tones your legs," says Peterson.

20. Chew gum
It burns a few calories — and it keeps you from mindlessly grazing, especially when you're cooking, says McGee.

21. Sleep better
A poor night's sleep causes people to chose less-nutritious foods, according to a study at the University of Pennsylvania. Another study showed that sleep-deprived people simply move less.

22. Walk and talk
Don't sit still when you take a phone call. At work, wear a headset.

23. Switch sides
Whether you're carrying a heavy bag on your shoulder or a child on your hip, "swapping sides every five minutes works more muscles," says Peterson.

24. Pick up the paceListen to fast songs, such as "Closer" by Ne-Yo, says Ruth Zukerman, co-owner of Flywheel Sports, a cycling studio in New York City. "The beat forces you to keep a calorie-burning pace, especially when walking or taking stairs."

25. Cook your own food"It's often healthier, and by the time you've made a meal and cleaned up, you've been on your feet a half-hour more than you would have waiting for takeout," says Slayton.

26. Go on a date.
Women tend to order foods with fewer calories when dining with a man (who's not a long-term significant other), compared with when they eat with other women, according to a study conducted at McMaster University in Hamilton, Canada.

27. Avoid eating lunch at your desk
If you must, have a quick bite, then go for a short walk.

28. Always carry a snack
Try nuts, low-calorie bars, or a piece of fruit. Eating frequently keeps your metabolism up (and reduces the odds that you'll wind up a victim of the vending machine).

29. Wear stilettos
"Every few days, I'll wear the highest heels I own," says Decker. "It helps tone my legs, because they work different muscles in my calves and thighs."

30. Relax
Stress causes the body to release cortisol, which causes more calories to be stored as fat, especially in your abdomen.

31. Watch less television
Adults who halved their television viewing time (by using an electronic lock-out system) not only burned an extra 119 calories per day, but did so without altering what they ate.

32. Lift upRise up on the balls of your feet and then lower yourself down again. "I do this little Pilates move everywhere," says McGee.

33. Build up your abs
Do intense bursts of engaging your abs tightly. If you think you can only do 30 seconds, push for 40, says Da Costa.

34. Drink a few cups of strong green tea every day
In addition to caffeine, green tea contains catechin polyphenols, plant chemicals that may also boost metabolism, according to a study from the University of Geneva in Switzerland.